Testosterone has long been the black sheep of hormones—blamed for every bad behavior from aggression to greed to promiscuity. But a new study might change testosterone's bad boy image.

Researchers at the University of Zurich asked 121 women—given a placebo or testosterone—to play a cooperation game. Known as the ultimatum game, one woman receives $10 and must give some of it to another woman. If the second woman refuses the gift, the first loses all her cash.

"Almost everybody believes that testosterone has these aggression-enhancing effects," Ernst Fehr—lead author of the study and a neuroeconomist at the University of Zurich, Switzerland—told the New Scientist.

While the hormone might cause aggression and greed, researchers believe that testosterone actually encourages men and women to improve their status.

If this were true, then participants receiving testosterone would fear being rejected, so they would present a more generous offer. Women who believed they had taken testosterone and actually ingested testosterone (and not the placebo) gave a dollar more than women who believed they had taken testosterone and swallowed a placebo.

When researchers probed them as to why they would give more money if they were given extra testosterone, the women reported that the hormone would make them "egotistic, more risk-taking, and more aggressive." But the researchers simply believe that the hormone worked to encourage women to improve their station.